<script type="text/javascript">
	// 属性描述对象:一个对象内部的数据结构
	var obj = {};
	obj.name = 'mjj';
	obj.name = 'alex';
	// console.log(delete obj.name);
	// console.log(obj.propertyIsEnumerable('name'));
	console.log(Object.getOwnPropertyDescriptor(obj,'name'));
	// console.log(obj.name);
	// name: 
	/*
	{
	value: alex,
	writable:true,
	enumerable:true,
	configurable:true,
	set:undefined,
	get:undefined
	}
	*/
</script>